[DOCS] Updates release notes

Author: picandocodigo

CHANGELOG.md

@@ -1,5 +1,10 @@
 ## 7.13.0
 
+### Client
+- Fixes thread safety issue in `get_connection` - [https://github.com/elastic/elasticsearch-ruby/pull/1325](Pull Request).
+
+## 7.13.0
+
 ### Client
 
 - Support for Elasticsearch version 7.13.0

docs/release_notes/713.asciidoc

@@ -1,6 +1,18 @@
 [[release_notes_713]]
 === 7.13 Release notes
 
+[discrete]
+[[release_notes_7131]]
+=== 7.13.1 Release notes
+
+[discrete]
+==== Client
+- Fixes thread safety issue in `get_connection` - https://github.com/elastic/elasticsearch-ruby/pull/1325[Pull Request].
+
+[discrete]
+[[release_notes_7130]]
+=== 7.13.0 Release notes
+
 [discrete]
 ==== Client